Monoterpenoid metabolism and aroma compounds are influenced by genetic characteristics. Linalool, α-terpineol, nerol, and geraniol are primary monoterpenoids that have previously been studied in grape (Vitis vinifera) berries. Previous studies were restricted by the lack of relevant studies investigating population structure and the regulatory mechanism underlying monoterpenoid synthesis. In this study, a total of 1133 alleles were amplified, with each locus having on average 6.06 alleles. We also assessed the genetic variability among the genotypes based on 187 microsatellite primer pairs amplified in 96 grape genotypes. The results of the phylogenetic tree analysis showed that the grapevine accessions grouped into five genetic clusters that largely coincided with the recognized species classification and the result of principal coordinates analysis (PCoA). The molecular characterization of these accessions provides insight into genetic diversity, population structure, and linkage disequilibrium (LD) in grapevines. A total of 51 quantitative trait loci (QTLs) were detected that were significantly associated with linalool, α-terpineol, nerol, and geraniol. We found that Deoxyxylulose phosphate synthase (DXS) was located in the region UDV060 on linkage group (LG) 5, whereas Farnesyl diphosphate synthase (FPPS) and Hydroxymethylbutenyl diphosphate reductase (HDR) were located in the VLG19-I-1 and VLG3-A-1 regions, respectively. These novel QTLs will potentially assist in the screening of aroma compounds in grapevines.
Xiaoxu Yang, Yinshan Guo, Junchi Zhu, Zaozhu Niu, Guangli Shi, Zhendong Liu, Kun Li and Xiuwu Guo
Xiaoxu Yang, Chang Liu, Zhishan Yan, Youjun Fan, Guojun Feng and Dajun Liu
Flowering time influences pod yield and quality of common bean (Phaseolus vulgaris); however, our knowledge of flowering time genes and flowering mechanisms in common bean remain limited. We performed RNA-sequencing (RNA-seq) analyses [long-day (LD) condition and short-day (SD) condition] to identify the flowering time genes and analyzed differentially expressed genes to examine their expression levels in relation to flowering time in ‘Hong Jin Gou’ common bean, a cultivar highly sensitive to photoperiod. The circadian patterns of related genes were identified using quantitative real-time polymerase chain reaction (qRT-PCR). Flowering time in ‘Hong Jin Gou’ was influenced by day length: SD conditions promoted flowering. A total of eight flowering time–related genes were identified, which were classified into photoperiod pathways. Homologs of pseudo-response regulator 5, pseudo-response regulator 7, and gigantea were more highly expressed under SD conditions than under LD conditions. Homologs of late elongated hypocotyl and timing of cab expression 1 were differentially expressed under light and dark conditions. Early flowering 3 is a key regulator of the pathway, which coordinates light and circadian clock inputs in leaves to trigger the expression of downstream genes. The present study provides critical information that could facilitate further investigations on the genetic mechanism of flowering time in common bean.